1 /*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "FwmarkClient.h"
18
19 #include "FwmarkCommand.h"
20
21 #include <errno.h>
22 #include <stdlib.h>
23 #include <string.h>
24 #include <sys/socket.h>
25 #include <sys/un.h>
26 #include <unistd.h>
27
28 namespace {
29
30 const sockaddr_un FWMARK_SERVER_PATH = {AF_UNIX, "/dev/socket/fwmarkd"};
31
32 } // namespace
33
shouldSetFwmark(int family)34 bool FwmarkClient::shouldSetFwmark(int family) {
35 return (family == AF_INET || family == AF_INET6) && !getenv("ANDROID_NO_USE_FWMARK_CLIENT");
36 }
37
FwmarkClient()38 FwmarkClient::FwmarkClient() : mChannel(-1) {
39 }
40
~FwmarkClient()41 FwmarkClient::~FwmarkClient() {
42 if (mChannel >= 0) {
43 close(mChannel);
44 }
45 }
46
send(FwmarkCommand * data,int fd)47 int FwmarkClient::send(FwmarkCommand* data, int fd) {
48 mChannel = socket(AF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0);
49 if (mChannel == -1) {
50 return -errno;
51 }
52
53 if (TEMP_FAILURE_RETRY(connect(mChannel, reinterpret_cast<const sockaddr*>(&FWMARK_SERVER_PATH),
54 sizeof(FWMARK_SERVER_PATH))) == -1) {
55 // If we are unable to connect to the fwmark server, assume there's no error. This protects
56 // against future changes if the fwmark server goes away.
57 return 0;
58 }
59
60 iovec iov;
61 iov.iov_base = data;
62 iov.iov_len = sizeof(*data);
63
64 msghdr message;
65 memset(&message, 0, sizeof(message));
66 message.msg_iov = &iov;
67 message.msg_iovlen = 1;
68
69 union {
70 cmsghdr cmh;
71 char cmsg[CMSG_SPACE(sizeof(fd))];
72 } cmsgu;
73
74 if (data->cmdId != FwmarkCommand::QUERY_USER_ACCESS) {
75 memset(cmsgu.cmsg, 0, sizeof(cmsgu.cmsg));
76 message.msg_control = cmsgu.cmsg;
77 message.msg_controllen = sizeof(cmsgu.cmsg);
78
79 cmsghdr* const cmsgh = CMSG_FIRSTHDR(&message);
80 cmsgh->cmsg_len = CMSG_LEN(sizeof(fd));
81 cmsgh->cmsg_level = SOL_SOCKET;
82 cmsgh->cmsg_type = SCM_RIGHTS;
83 memcpy(CMSG_DATA(cmsgh), &fd, sizeof(fd));
84 }
85
86 if (TEMP_FAILURE_RETRY(sendmsg(mChannel, &message, 0)) == -1) {
87 return -errno;
88 }
89
90 int error = 0;
91
92 if (TEMP_FAILURE_RETRY(recv(mChannel, &error, sizeof(error), 0)) == -1) {
93 return -errno;
94 }
95
96 return error;
97 }
98